Abstract 12093: Bi-Ventricular Cardiac Adaptations to 20 Weeks of High-Intensity Resistance Training in Healthy Untrained Men: A 3D Echocardiography Longitudinal Study

Abstract

Introduction: The historical description of cardiac remodelling between strength and endurance athletes, made by Morganroth in the 1970s, has been challenged with the advancements in our understanding of the protective effect of Valsalva manoeuvres and the emergence of sophisticated imaging techniques for cardiac function assessment. Objective: We aimed to analyze the kinetics of muscular and cardiac responses to 20 weeks of high-intensity resistance training in healthy untrained volunteers. Methods: A total of 27 young and healthy men with an average age of 22.8±3.2 years participated in a 20-week strength training program. The training program intensity was guided by 1-Repetition Maximum (RM) testing. Before and after 12 and 20 weeks of training, participants were assessed using body composition analysis, electrocardiogram, 3D transthoracic echocardiography, cardiopulmonary exercise testing ( V O 2peak ), and muscle isokinetic dynamometry. Anova was utilized to analyse time effect. Results: Among the initial cohort, 22 subjects completed the study protocol. Arterial blood pressure significantly decreased at both time points. Isokinetic evaluation confirmed increases in maximal strength for quadriceps (Δ 0-20wk =+46.8Nm, P<0.001), hamstrings (Δ 0-20wk =+25.3Nm, P=0.025), triceps (Δ 0-20wk =+11.6Nm, P=0.005), and biceps (Δ 0-20wk =+9.2Nm, P=0.023). Regarding cardiac analysis, after 20 weeks of training 3D left ventricular (LV) mass increased (120.1±15.4 to 133.7±16.3 g, P=0.018), with an augmentation in both septal wall (6.1±1.1 to 7.2±1.4 mm, P=0.027) and posterior wall thickness (5.5±1.3 to 7.1±1.3 mm, P<0.001). 3D LV end-diastolic volume increased by 7.28% without reaching a significant difference. Right ventricular (RV) wall thickness also increased (3.33±0.73 to 3.89±0.8 mm, P=0.04), with a slight non-significant augmentation of 3D RV end-diastolic volume by 7.89%. No significant changes were found in LV and RV systolic or diastolic function. Conclusions: This study demonstrated that our 20-week high-intensity strength training program resulted in a rapid and significant increase in muscular strength. The cardiac response to strength training showed a moderate biventricular response like that of endurance athlete